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UP: Fachverband Umweltphysik

UP 1: Oceanography and Climate Modelling

UP 1.6: Talk

Thursday, September 2, 2021, 12:15–12:30, H3

Water tracers in the general circulation model of intermediate complexity PlaSim — •Oliver Mehling¹, Elisa Ziegler¹, Heather Andres², Frank Lunkeit³, Martin Werner⁴, and Kira Rehfeld¹ — ¹Institute of Environmental Physics, Heidelberg University, Germany — ²Memorial University of Newfoundland, St. John's, NL, Canada — ³CEN, Institute of Meteorology, University of Hamburg, Germany — ⁴Alfred Wegener Institute, Bremerhaven, Germany

Atmospheric water tracers provide a powerful tool to examine source-sink relations of water vapor in atmospheric general circulation models (GCMs). In particular, they offer insight into the variability of moisture transport and sources of precipitation. However, water tracers are computationally expensive, and allow only for short simulations or a small number of tracers in state-of-the-art models.

Here, we present the implementation of water tracers in a GCM of intermediate complexity, the Planet Simulator (PlaSim), which permits for millennial-length simulations with water tracers. We first show that the model can reproduce present-day precipitation patterns reasonably after tuning, and discuss the validation and remaining biases of the tracer-enabled model.

The water tracer framework is then applied to study moisture export from the Arctic in idealized experiments of warm and cold climate states using simulations forced by sea surface temperatures and sea ice concentrations from comprehensive Earth system models. We discuss the contributions of moisture evaporated in the Arctic to precipitation at high latitudes, both in the mean state and during extreme events.